Waipaoa River, New Zealand

 

Funding Agency:  NSF

Summary:  Continental margins have long been recognized as important and rich reservoirs of information on earth history, and contain a detailed record of climate, geomorphic evolution and land-use practices, sea level, tectonics, and oceanographic processes.  As compared with the deep-sea record, margins have a far greater potential to preserve high-resolution continental records because of their proximity and high sediment inputs from rivers.  Despite this recognition, and concerted scientific efforts over past decades, scientists presently lack the ability either to accurately predict stratigraphic development of margins given a realistic set of controlling processes, or to reconstruct these processes from the stratigraphic record. 

The MARGINS Source-to-Sink community (S2S) has concluded that to attain this level of understanding, holistic studies of margins should be undertaken to investigate the generation, transfer and accumulation of sediments over multiple timescales, from terrestrial uplands to marine basins.  This proposal focuses on the sedimentary signals preserved within the Holocene shelf mud deposit off the Waipaoa River (NZ), a MARGINS focus area selected through broad community input.  The proposed work represents a natural complement to other MARGINS Waipaoa field-based proposals being submitted during this cycle, and is an essential component of parallel community modeling efforts that propose to model the entire source-to-sink system of the Waipaoa. 

 

Objectives:  The major objective of this study is to determine the nature and resolution of the Mid-Late Holocene marine stratigraphic record off the Waipaoa with respect to known terrestrial and oceanographic changes. This research would test specific hypotheses regarding the efficacy of the shelf mud deposit in recording well-documented changes in the adjacent terrestrial environment, including a remarkable 2250 year record of major flood events from lake records, as well as Mid-Holocene and Historical perturbations in sediment input, driven by ENSO, volcanism, tectonics, and European deforestation.  Because of the high supply of sediments, and a tectonic shelf basin which traps much of these sediments, the Waipaoa shelf offers an exceptional opportunity to examine the degree to which terrestrial, climatic and anthropogenic signals are propagated onto an active shelf and preserved in its strata.

 

Collaborators: 

NIWA: Geffroy LeMarche, Alan Orpin, Helen Neil

Victoria: Lionel Carter

GNS: Noel Trustrum

DUKE: Lincoln Pratson and Tommy Gerber

Massey: Alan Palmer

East Carolina University: J.P. Walsh

Skidaway Institute of Oceanography: Clark Alexander

University of Otago: Gary Wilson

California State University Northridge: Kathie Marsaglia

mariond

 

Equipment/ Research Vessels/ Methods: 

Equipment used to perform field work included:  high-resolution (Chirp)
reflection and sidescan, vibra-coring, multisensor core logging, box, kasten, and
calypso (marion durfesne) cores. 

Research Vessels included the RV Kilo Moana and the RV Marion Dufresne

Chronostratigraphic analysis of sediment cores will be facilitated by the numerous
well-constrained tephra layers within the time-period of interest, as well as recent
deposition rates from radioisotope geochronology. 

 

RV Kilo Moana
RV Marion Dufresne
crew